Specific cellular immune responses and effect against subcutaneously transplanting tumor induced by DNA vaccine of HBV surface gene in mice

Objective To observe the specific immune responses and the protection against P815 mastocytoma cells stably expressing HBV surface antigen in H-2 d mice after DNA immunization of HBV surface antigen gene (pCR3.1-S). Methods The immunization was performed by intramuscular injection of DNA vaccine (pCR3.1-S). P815-HBV-S was inoculated subcutaneously into mice three weeks after DNA immunization. The tumor growth was measured every five days. HBsAg specific cytotoxic T lymphocyte (CTL) activity was measured by 51 Chromiunm release assay. Results HBV DNA vaccine can evidently inhibit the tumor growth, prolong the survival period and improve the survival rate in mice. Meanwhile, HBsAg specific CTL activity was obviously increased after DNA immunization. Conclusions The results show that the DNA vaccine, pCR3.1-S, has strong antigenecity in cellular immunity and has marked killing effect on HBV infected cells in vivo. DNA vaccine against HBV may be useful for both prophylactic and therapeutic purposes.